In the chiasmic gorges beneath these mountains and their glaciers, flow rivers wild and wonderful that nourish tiny hamlets and villages like Hunza, the fabled Shangri-la from the pages of James Hilton’s Lost Horizon.

The verdant, gentler hills of the Pir Panjal, including the incomparable Kaghan valley, the moulded contours of the lower valleys of the Hindu Kush, like Swat and Chitral, the Himalayan valleys of Astor and Skardu (all perfectly counter pose the harsh), forbidding grandeur of the Karakoram and Pamirs.

Fed by the snowmelt and monsoon runoffs, great rivers like the Jhelum and the Indus are born in these mountains and gather momentum to bestow their bounty downstream on a land brought to fecund life by the spring and summer sun.

Winder is long and summer brief in the Roof of the world among the gable cliffs, ice cornices, vaulted pillars, sliding glaciers, and rock buttresses, chipped and carved into strange and eerie sculptures by the cutting edge of the sub-zero blasts.

Only in late Mary or early June do the snow-clad passes open, some to close again in September. Constantly on the move, pitted with deadly unseen crevasses hundreds of meters deep, the glacier add the finishing touch to the most dramatic, if desolate, landscape in the world.

G.T. Vigne was the first to bring back an account of this, one of the world’s greatest glacial systems, at a time when geographers were sceptical (as they were about ice on the Equator) that any glaciers could exist in warmer latitude than those of the European Alps.

Colonel H. H. Godwin-Austen, after whom one of the glaciers is named, added graphic insight into the system through his sketches and observations. Through blizzard, frost, and storm the surveyors moved forward, victim of altitude sickness, frostbite, and snow blindness. At times lightning set their hair ablaze.

They had to hump heavy equipment, including forty-five kilo (100-lb) theodolites, over mountains and across raging rivers, from one high point to another. Setting up a “trig” station in the most forbidding places, the surveyor then computed the angles between one base line, his station and a third point.

So accurate were these measurements that a series carried over hundreds of kilometres erred by no more than a fraction of a centimetre for each bas kilometre. Sometimes at altitudes of 4,570 metres (15,000 feet) or more, they had to dig down through several metres of snow to find a stable, level base on which to build a stone pillar for the theodolite.

Godwin Austen’s success rested not on his scientific skills alone. He was also a magnificent mountaineer. He had to be. Year after he broke the world’s altitude record, from 5,973 meters (19,600 feet) to 6,065 meters (19,900 feet); from 6,278 meters (20,600 feet) to 6,400 meters ( 21,000 feet), at which height he built a “trig” station; until finally he stood at 6,827 meters (22,300 feet). Four of his stations were the world’s highest for more than sixty years.

His descriptions of the glaciers and mountain were stirring. The endless, anguished creaking of rock and ice in mortal combat, moaning as if in agony (a noise sometimes drowned in the tearing), screaming, thundering frenzy of an avalanche, creates one of the most distinct phenomena of life in the Karakoram.

The extremes of temperature are the most severe in the world. In summer, rocks become so hot that they blister the skin. In the long winter, it is the coldest inhabited place on earth.

The fact that people can live at altitude of 3,658 metres (12,000 feet) or more, and survive the cutting edge of winds that blast against mountain peak and funnel furiously through passes and ravines, gives fresh scale to concepts of human endurance and hardihood.

Such a tangled knot of might peaks also gives new scale to human perspectives. The clasp of mountains that decorates the world’s midriff is unique. A “Silk Route” through these desolate mountain fastnesses existed long ago. Unmindful of the hazards, for more than 2,000 years traders and mule trains carried silk, tea and porcelain from China over this tortuous route via the Khunjerab Pass to the subcontinent, to barter for gold, ivory, jewels and spices.

Until 1891 the only fair weather footpath to Gilgit from Kashmir in the south was over the hazardous 4,175 meters high (13,700 feet) Burzil Pass, across the Deosai Plains and through the Astor Valley to Bunji. The journey took about a month. Covered with deep snow and ice for more than half the year, the desolate Deosai Plains above the pass; stretch for more than nineteen kilometers (12 miles).

In 1892 another route was opened through the Kaghan Valley and across the 4,170 meters high (13,685 feet) Babusar Pass. But both could only be used for three month of the year before the snows fell again. Many have been trapped and frozen to death.

These districts were finally opened up by the Karakoram Highway, which in the course of its 883 kilometers long (548 miles) journey from Thakot rises, through the Himalaya and the Karakoram Mountains, to more than 4,570 meters (15,000 feet) and is one of the great engineering marvels of the world.